It seems to me that opportunity is the source of domination not capitalism per se. People dominate if they have the opportunity and if they think they can get away with it. Capitalism creates opportunities for domination (colonialism, slavery, "free" trade agreements, monopolies, bottlenecks, economic rents). But capitalism is one of just many forms of domination.
Men have a slight physical size advantage over women, and that's led to millennium of domination in the form of patriarchy. So that's domination that springs from how biological difference creates opportunity.
Catholic priests are trusted in the community -- and research from the Catholic priest abuse scandal shows that they committed pedophilia at twice the rate of the average population (8% of Catholic priests are pedophiles as compared with 4% of men in the general population). The Catholic priest example is telling because it's so clearly not capitalism as the driver of domination. It's socially created but distinct from capitalism.
There is a notorious case in Australia right now involving Rolf Harris who was a beloved entertainer -- who used his celebrity to abuse children for decades. So too in the UK, the entertainer Jimmy Savile, used his celebrity to sexually abuse upwards of 1,000 people over his lifetime. This is a variation on the Catholic priest abuse scandal -- where trust, in this case the trust that comes with celebrity, enabled these men to get away with these crimes for decades. The Jerry Sandusky sex abuse scandal in the U.S. is similar -- in that case the celebrity and trust associated with collegiate athletic success created the opportunity for abuse. People who work with disabled children (particularly those with limited or no speech) will tell you that nearly 100% of these children are abused at some point in their life (the perceived inability of the child to ever report the crime creates the perception of opportunity).
We often see men as the drivers of domination, but women in positions of authority -- Mother Theresa, Margaret Thatcher, Arianna Huffington -- are notoriously cruel. So that's another variation of socially created forms of domination, but independent of biological sex.
But then here's the question: Not all people who have the opportunity to commit acts of domination, choose to do so. Many find domination abhorrent and would not even consider it. So what explains the fact that most people, when given the opportunity to commit acts of domination, choose not to do so?